Searching PubMed Using MeSH Search Tags
You may also choose to search a MeSH heading and a subheading combination using the AND Boolean operator and the subheading field tag of [sh]. This may be done when you want to search for a subheading concept that cannot “legally” be attached to the MeSH heading you are also searching.
hypertension [mh] AND toxicity [sh]
To turn off the subheading grouping, use the tag [sh:noexp]. Do this only when using an unattached subheading.
finger injuries [mh] AND surgery [sh:noexp]
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